org.apache.hadoop.metrics2.MetricsTag.java Source code

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Here is the source code for org.apache.hadoop.metrics2.MetricsTag.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.hadoop.metrics2;

import com.google.common.base.Objects;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;

import java.util.StringJoiner;

import static com.google.common.base.Preconditions.checkNotNull;

/**
 * Immutable tag for metrics (for grouping on host/queue/username etc.)
 */
@InterfaceAudience.Public
@InterfaceStability.Evolving
public class MetricsTag implements MetricsInfo {
    private final MetricsInfo info;
    private final String value;

    /**
     * Construct the tag with name, description and value
     * @param info  of the tag
     * @param value of the tag
     */
    public MetricsTag(MetricsInfo info, String value) {
        this.info = checkNotNull(info, "tag info");
        this.value = value;
    }

    @Override
    public String name() {
        return info.name();
    }

    @Override
    public String description() {
        return info.description();
    }

    /**
     * @return the info object of the tag
     */
    public MetricsInfo info() {
        return info;
    }

    /**
     * Get the value of the tag
     * @return  the value
     */
    public String value() {
        return value;
    }

    @Override
    public boolean equals(Object obj) {
        if (obj instanceof MetricsTag) {
            final MetricsTag other = (MetricsTag) obj;
            return Objects.equal(info, other.info()) && Objects.equal(value, other.value());
        }
        return false;
    }

    @Override
    public int hashCode() {
        return Objects.hashCode(info, value);
    }

    @Override
    public String toString() {
        return new StringJoiner(", ", this.getClass().getSimpleName() + "{", "}").add("info=" + info)
                .add("value=" + value()).toString();
    }
}